In recent years, there has been a growing awareness of various problems that are particularly inherent in the operation of printing presses. It is known, for example, that ink keys in an ink fountain are more often than not out of square to the fountain roller and/or otherwise fail to meet the desired specifications. As such, uniform ink film thickness across the fountain roller is impossible to set, and color matching is difficult, if not impossible, to successfully achieve.
In one practical example, it was found from actual measurements that ink keys on a conventional fountain assembly were out of square by an average of 0.009". This quite simply means that, for an ink key that is approximately 1.5" in width, one end of the key is 0.009" out of square to the other end. As will be recognized by the skilled artisan, a 0.009" out of square measurement will not allow proper ink adjustment in the zone of that ink key on the ink fountain assembly.
To solve this problem, it has been proposed that a steel key be positioned permanently in the center of the fountain. The thinking behind this proposal is to minimize the effect of accumulative errors across a typical fountain of 24 keys inasmuch as only 12 keys on each side of the fountain center can be skewed, thereby reducing the error in half. Although this concept is an improvement on original fountain designs, it simply does not prevent the keys from being undesirably skewed.
In addition to the foregoing, there is a problem in connection with the adjustment of the keys in relation to the fountain roller. More specifically, it is known from testing that ink key movement does not correlate with the LED lights at the press console, but, rather, the LED lights move when the typical potentiometer driven by the ink key motor moves, which is not an indication of actual key movement. During actual testing, it was found that delays as long as four (4) seconds were encountered from the time the switch for key movement was depressed by the pressman at the press console until the key actually moved at the fountain assembly. As a result, the pressman is at a total disadvantage, particularly since it is impossible to know in which direction the key last moved.
In this connection, when a key is moved in the same direction, it has been typical for the dead time to be from one (1) to two (2) seconds maximum. 0n the other hand, when the key reverses direction, that time can be as long as three (3) to four (4) seconds before the ink key actually moves. As will be appreciated, this makes it very difficult for the pressman to make precise four color moves without knowing when the key is actually moving.
From the foregoing, it would be highly desirable to sense actual ink key movements more accurately at the console, using the conventional LED's on the press console of the printing press. There are typically 50 LED's represented in the closed to fully opened position, with each light representing 2% of movement. Unquestionably, it would be beneficial to know when actual key movements occur so that precise color moves can be accomplished in the shortest period of time to reduce makeready and run waste.
The present invention is directed to overcoming one or more of the foregoing problems and achieving one or more of the resulting objects.